This is a note to let you know that I've just added the patch titled rcu-tasks: Don't delete holdouts within trc_wait_for_one_reader() to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: rcu-tasks-don-t-delete-holdouts-within-trc_wait_for_.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 6bd294c18ca98ce0b2edb5218e9a3921b2e96ea2 Author: Paul E. McKenney <paulmck@xxxxxxxxxx> Date: Tue May 25 11:28:40 2021 -0700 rcu-tasks: Don't delete holdouts within trc_wait_for_one_reader() [ Upstream commit a9ab9cce9367a2cc02a3c7eb57a004dc0b8f380d ] Invoking trc_del_holdout() from within trc_wait_for_one_reader() is only a performance optimization because the RCU Tasks Trace grace-period kthread will eventually do this within check_all_holdout_tasks_trace(). But it is not a particularly important performance optimization because it only applies to the grace-period kthread, of which there is but one. This commit therefore removes this invocation of trc_del_holdout() in favor of the one in check_all_holdout_tasks_trace() in the grace-period kthread. Reported-by: "Xu, Yanfei" <yanfei.xu@xxxxxxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 208acb286ec2..b338f514ee5a 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -908,7 +908,6 @@ static void trc_wait_for_one_reader(struct task_struct *t, // The current task had better be in a quiescent state. if (t == current) { t->trc_reader_checked = true; - trc_del_holdout(t); WARN_ON_ONCE(t->trc_reader_nesting); return; }